Helmet accessory



FIG. 1 is a front perspective view of a helmet accessory showing my newdesign;

FIG. 2 is a front elevation view thereof;

FIG. 3 is a rear elevation view thereof;

FIG. 4 is a left side elevation view thereof, the right side being amirror image;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof.

The details shown in broken lines form no part of the claimed design.

CLAIM The ornamental design for a helmet accessory, as shown anddescribed.